The use of holograms to store optical information has been well documented in the prior art. In general, an array of holograms, or sub-holograms, are holographically formed on a photographic plate and a deflection system is used to deflect a reference beam so that it passes through a selected one of the sub-holograms. The stored information on each sub-hologram can be individually reproduced by well known techniques.
Although the prior art has succeeded in increasing the packing density of information which can be recorded on holographic plates, the readout rate of such information has been limited by both the low precision of the light deflection device utilized and the size of the holographic plate. In particular, the amount of information which can be recorded on the holographic plates is restricted by the deflection angle characteristics of the readout scanning light beam and the size of the holographic plates, effectively limiting the information capacity of a holographic memory.